The model is Seamaster, approx. mid to late 60's. To determine more exactly you'll have to take photos of the reference number found on the inside caseback and the serial on the movement. Any competent, experienced watchmaker can replace the crystal for you and source one that's OEM but it's even better if you utilize a watchmaker who has an Omega parts account. At any rate, you should also have the watch fully serviced if you're unsure of when this was last done. Costs vary greatly. Expect to pay anywhere from $200USD and up for a crystal replacement and service, more if replacement parts are needed. Cheers.
Click to expand...